Subsurface Analysis Using Gravity Data at Lili Sepporaki Geothermal Area

Indonesia Malaysia Research Consortium Seminar 2018

Sihombing, Jubilate^1 ; Lestari, Wien^1 ; Mariyanto^1 ; Joni, Wiwid^2

Geophysical Engineering Department, Faculty of Civil Enviromental and Geo Engineering, Institut Teknologi Sepuluh Nopember, Indonesia^1

Center of Mineral Resources, Coal and Geothermal, Ministry of Energy and Mineral Resources, Indonesia^2

关键词: 3-d inversions;    Bouguer anomaly;    Geothermal areas;    Geothermal systems;    Inversion models;    Sub-surface imaging;    Subsurface structures;    Surface manifestations;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/588/1/012009/pdf
DOI  :  10.1088/1757-899X/588/1/012009

来源: IOP

【 摘 要 】

Gravity survey plays an important role in early stage of subsurface imaging in geothermal system. The aim of this study is to understand the subsurface structure and possibly the heat source based on rock density distribution with three dimensional inversion modeling (3D). In 2010, Center of Mineral Resources, Coal and Geothermal of Indonesia was performed gravity survey at Lili Sepporaki geothermal area with 205 stations within a 10 x 10 km coverage area. The complete Bouguer anomaly was obtained with the density of 2.8 g/cm3 and this density was used to do 3D modelling. Bouguer anomalies ranging from 40 mgal to 62 mgal were observed in the study area with low anomalies values located in the northern part and high anomalies located in the southern part of the study area. Based on the 3D inversion modeling results, there are low density rocks with values between 2.0 - 2.3 g/cm3 around the hot springs of the research area with a depth of 2 km. This rocks are interpreted as intrusive igneous rocks and are thought as the heat source of geothermal systems in the study area.